Answer:
x² + 12x - 13 = 0
Explanation:
12x = 13 - x²
the standard form of an equation is written starting from the variable of the highest degree to the lowest. Hence after rearranging;
0 = 13 - x² - 12x
0 = -x² - 12x + 13
In an equation, the highest degree of a variable should preferably be postive hence the equation to the left side to remove the negative sign:
x² + 12x - 13 = 0